Elastic-fluid turbine.



S. J. PIGOTT.

ELASTIC FLUID TURBINE.v

APPLICATION rum) AUG. 18, 1911.

1,021,260. Paiented Mar. 26, 1912.

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. UNITED STATES PATENT OFFICE.

STEPHEN J. PIGOTT, OF ST. ANNS, I-IELENSBURG-H, SCOTLAND, ASSIGNOR TOGENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELASTIC-FLUID TURBINE.

To all whom it may concern:

Be it known that I, STEPHEN J. PIeo'rT, a citizen of the United Statesof America, residing at St. Anns, Helensburgh, Scotland, have inventedcertain new and useful Improvements in Elastic-Fluid Turbines, of whichthe following is a specification.

My invention relates to elastic-fluid turbines, and more particularly ofthe type used for marine propulsion and has for its ob ect to improvethe efficiency of such turblnes at different powers and speeds.

My invention comprises a main or highpower turbine and a cruising orlow-power turbine mounted on the same shaft, the crulsing turbine whenrunning idle being connected to a low pressure stage of the mainturbine. The cruising turbine when in operation exhausts throughsuitable valve-controlled nozzles into the main turbine and, in order toprevent abnormal increase of pressure in the cruising turbine in theevent of failure to open said valves, a by-pass connection controlled byan automatic valve is provided between the two turbines.

The accompanying drawings illustrate one arrangement for carrying myinvention into eflect, Figure 1 being a part longitudinal sectionthrough the turbine illustrating the means by which motive fluid isadmitted when full power is required; and Fig. 2 is a similar viewillustrating the means by which motive fluid is admitted at low power orcruising speeds.

In carrying my invention into effect as illustrated in the drawings, themain turbine consists of a number of impulse stages 1 and one or morereaction stages 2. A cruising or low-power turbine 3 of the impulse typeis mounted on the same shaft as the main turbine, and is housed in thecasing in such manner that it is isolated from the main turbine whenfull power is being developed, by means of a diaphragm in which theinlet valves for controlling the passage of steam from the cruising tothe main turbine are located. The cruising turbine is shown asconsisting of a single stage impulse wheel, but it may consist of anynumber.

In order to prevent leakage of steam from the high pressure stage of themain turbine into the cruising turbine when the main turbine is working,I provide the diaphragm 4 between the two with a labyrinth shaft pack-Specification of Letters Patent.

Application filed August 18, 1911.

Patented Mar. 26, 1912.

Serial No. 644,801.

ing 5. It may also be provided with carbon ring packing 6 held in placeby a garter spring. Any other suitable packing device than thatillustrated may be used. Should any fluid pass through this packing intothe cruising turbine casing, it would tend to lower the efficiency ofthe main turbine, and to overcome this objection I connect the cruisingturbine portion of the casing by a pipe 7 with a low pressure stage ofthe main turbine, so that a low pressure may be maintained in thecruising turbine while the main turbine is in operation, and also sothat the motive fluid which has leaked through may be returned to themain turbine, where it can do useful work. This pipe is controlled bythe valve 8.

The motive fluid can be admitted to these turbines by any suitable typeof valve. In the drawing I have illustrated a double beat valve 9situated in the main steam pipe. This valve is adapted to admit motivefluid alternatively to the first stage 1 of the main turbine or to thecruising turbine 3. When the cruising turbine is in operation, theexhaust fluid from it passes through the main turbine by means of valves10, Fig. 2, controlling nozzles 11 in the diaphragm separating the mainturbine from the cruising turbine, and these valves should be openedbefore the double beat valve is opened to supply the low power turbinewith steam. In the event of these valves being inadvertently leftclosed, the pressure in the cruising turbine might rise to the pressureof the boiler or other source, and to prevent this I provide a pressurecontrolled escape valve 12, set so as to open at any desired pressureabove the normal working pressure, and by-pass the fluid through theconduit 13 into the first stage of the main turbine. In order to callattention to the fact that the valves 10 have not been opened, I mayprovide a small blow-off valve or steam whistle 14, set to blow off andso give a warning when the pressure rises a certain predetermined amountabove the normal working pressure.

In order that the structure of the turbine used to illustrate myinvention may be understood, the following description is given: Thediaphragm 4 is provided with the nozzles 11, previously referred to, andalso with nozzles 15 through which live steam enters from the supplyconduit 16,

under the control of a suitable valve means. Steam from both nozzlediaphragms act on the wheel buckets 17 to drive the Wheel or rotor 18.Between the rows of wheel buckets are stationary intermediate buckets 19whose function it is to receive steam from one row of wheel buckets andproperly direct it against the next. The structure is the same in thesubsequent impulse stages, the only difference being that the nozzlesand buckets are larger to accommodate the increased volume of steam dueto the decreased pressure. Between the impulse stages of the high powerturbine are diaphragms 20 having packings 21 of suitable constructionthrough which the shaft 22 extends.

I have omitted some of the buckets for the lower pressure stages of thisturbine for the purpose of simplifying the illustration.

In order to change the power developed by the high-power turbine, steammay be admitted through the nozzles 15 'to its initial stage or throughconduit means 28 to a stage of'lower pressure under the control ofsuit-able valve means. In the low pressure end of the turbine the rotorbuckets 24 are mounted on a drum 25, and the intermediate buckets 26 arecarried by the main casing 27 which carries all of the intermediates forboth the high and low power turbines. The low-power turbine is providedwith fluid admitting nozzles 28, and wheel and intermediate buckets 29and 30.

Instead of exhausting the fluid from the cruising stage directly intothe first stage of themain turbine, it will be obvious that one or moreof the stages of the main turbine may be by-passed and the fluidadmitted to a stage at lower pressure. It will also be obvious thatvarious modifications may be made in the construction and design of thevarious parts without departing from my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. An elastic-fiuid turbine comprising a highand a low-power turbinemounted on the same shaft and within the same casing, with a valvecontrolled connect-ion between the low-power turbine casing and one ofthe low pressure stages of the high-power turbine to insure that thelow-power turbine will rotate in a low pressure atmosphere when thehigh-power turbine is in operation.

2. An elastic-fluid turbine comprising a highand a low-power turbinemounted upon the same shaft within the same casing, but separated fromeach other, the lowpower turbine being connected to a low pres surestage of the high-power turbine when the latter is in operation and thehigh-power turbine receiving the exhaust of the lowpower turbine whenthe low-power turbine is in operation.

3. An elastic-fluid turbine comprising a highand a low-power turbinemounted within the same casing, a shaft common thereto, valves arrangedto control the passage of exhaust fluid from the low-power turbine tothe first stage of the high-power turbine, and an automatic valvearranged to bypass the exhaust steam to the high-power turbine from thelow-power turbine in the event of the failure of the first named valvesto open.

1. An elastic-fluid turbine comprising a highand a low-power turbinemounted within the same casing, a shaft common thereto, valves arrangedto control the passage of exhaust fiuid from the low-power turbine tothe first stage of the high-power turbine, and an automatic valvearranged to bypass the exhaust steam to the high-power turbine from thelow-power turbine in the event of the failure of the first named valvesto open, and a signal device which operates when the pressure in thelow-power turbine rises above a predetermined value.

5. An elastic-fluid turbine comprising a high-power multi-stage turbineand a lowpower turbine, a casing common to both turbines, a shaft alsocommon to both, a conduit connecting the low-power turbine with one ofthe low pressure stages of the highpower turbine, a valve in saidconduit, and an admission valve that alternatively admits motive fluidto the said turbines.

6. In combination, a high-power turbine comprising a plurality ofstages, a lowpower turbine, a casing common to both turbines, adiaphragm in the'casing that separates the two turbines, nozzles thatsupply live steam to the high-power turbine, other nozzles that supplyexhaust steam from the low-power turbine to the high-power turbine forcruising speed conditions, valve means for admitting steam to theturbines, and valve means that control the passage of steam throughnozzles conveying steam from the lowto the high-power turbine.

7. In combination, a high-power turbine comprising one or more impulsestages, and a reaction portion, an impulse low-power turbine, a shaftcommon to said turbines, a conduit connecting the casing of the lowpowerturbine with a low-pressure stage of the high-power turbine when thelatter onlyis in service, conduits for conveying steam at high pressureto said highand low-power turbines, valve means controlling theadmission of steam to the turbines, and other valve means controllingthe passage of steam from the lowto the high-power turbine for operatingat cruising speed.

8. In combination, a high-power turbine comprising one or more impulsestages and a reaction portion, an impulse low-power turbine, a shaftcommon to said turbines, a conduit connecting the casing of thelowturbines, a connection between the two that is open only when theformer is in service, a connection for supplying steam from the lowtothe high-power turbine which is open only when both turbines are inoperation, and a shunt from the lowto the highpower turbine which isresponsive to pressure conditions in the low-power turbine.

In witness whereof, I have hereunto set my hand this 13th day of July,1911.

STEPHEN J. PIGOTT. Witnesses:

HAROLD MCCUNN, FRED MIDDLETON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

